building harbours, quay walls etc.

As we all learnt when playing on the beach with a bucket and spade as kids… you can’t build anything solid on lose sand.

As you travel around the coast on your holidays your very likely to be attracted to the sandy coves with a picturesque harbour nestling in a corner… all built hundreds of years ago in many cases. bearing in mind the difficulty of digging wet sand to get access to sound foundations… how on earth were these harbours constructed without the aid of diving gear and modern lifting equipment in the time given between the tides. How were deep water quays built and the structures such as the Solent forts… built directly onto the seabed… and then wells dug to get fresh water without the ingress of seawater…

I'm not sure how relevant this may be but in the late 1780s when William Gandon was constructing Dublin's new Custom House he was faced with a similar dilemma. The Port & Docks Board insisted on a particular site which was situated on a wide curve which only fifty years before had been a sandbank in the bay between two tidal channels. Excavating to bedrock was almost impossible - the more one dug the more susceptible the hole was to inundation when the tide came in. Shifting and collapsing foundations plagued the work and threatened the necessity to abandon the project, especially when the number of fatalties began to rise.

Gandon's solution was lauded as genius later, but whether it was one he invented or "borrowed" from contemporaries is a moot point. The same technique was discovered to have been used in Holyhead in a pier revampment some years earlier. He sank several pillars to the bedrock at specific points and then "bridged" the expanse between with large stones literally sitting on the sand, which were cemented together. These he built up in layers in a conventional style except for the crucial fact that he set a membrane between each layer rather than cement - in his case he used silk. On the side fronting the river he had conduits inserted at intervals within the foundation wall. The enclosed area was emptied of sand and replaced with shale. This technique was used to a level just under ground level at which point a more conventional structure was plonked on top.

Essentially what he achieved was a "floating" building in that the tidal waters could pass through the substructure relatively unhindered, The stones still provide the bulk of the support for the massive superstructure above. The pillars simply prevent lateral shift. Maybe a similar technique in more basic style has been used elsewhere traditionally?

I'm afraid I'm immediately going off topic but this might interest you. I don't know anything about building harbours but but when it comes to the problems of construction below the high tide mark, this example shows what was being accomplished in the 16/17th c. http://canmore.rcahms.gov.uk/en/site/48064/details/culross+the+moat+coal+shaft/?date=asc&biblio=moreThere is about the Culross Moat Pit, the first known undersea mine workings just offshore in Fife. There is an excellent paper which goes into detail and explains the use of coffer dams in this instance and presumably a similar method was used in the construction of some harbours. http://www.euppublishing.com/doi/abs/10.3366/E1471576709000400 Click PDF + and it should be there, if it isn't, let me know and I'll try to precis it.On p. 189 it discusses the construction of the pier which served the pit.

If you're ever in the area on one of your trips north bandick, Culross is the most wonderfully preserved little town and in its layout gives a remarkable good facsimile of what medieval Glasgow must have been like from the abbey on the hill behind the the town to the residential,commercial and industrial area by the waterfront.

Last summer Michael Wood and the BBC organised some excavation on the remains of the Moat Pit for a forthcoming programme, when I was over there in the spring they were advertising for volunteers to help clear the mud and seaweed, even I would find that a less than attractive prospect. Here's a pic. of them working on the remains of the shaft.http://www.s1culross.com/files/photo/max-307988.jpg

Interesting nordman… I was 2nd eng on a tug that towed a linkspan bridge from Amsterdam to the new ferry terminal being constructed in Rosslare southern Ireland. Once offloaded from the barge being used to transport the bridge we were to tow the barge back to Immingham.

There were many construction problems which held us up getting away and left us stuck on site next to the new jetties where it was intriguing watching the construction methods. I noted they too laid a ‘membrane’ of what seemed to me fibreglass matting before the infilling of the jetty walls. How this flimsy cloth like fabric was to serve any purpose when they were dumping thousands of tons of rock and ballast on it was beyond my comprehension… but my thoughts were to soon be preoccupied in organising the flooding of the ballast tanks… partially submerging the barge to float the bridge off the barge. I think that took over a week in itself.

But as you mention a ‘membrane’… could this idea have been used in the construction of some of the canal system… I’m sure this now sounds familiar.

It’s the construction of the harbour walls that I’m having trouble understanding… finding something solid to begin building on, digging it out and laying foundations during the tides…

I was engaged in the dredging of ST Aubin’s harbour on Jersey in the Channel Islands… where the tide leaves the harbour… I won’t say high and dry as it was full of mud… as soon as was practical a stream of JCB diggers and bulldozes came in through the harbour entrance and gradually scooped up the mud into the barge I was working that had settled on the bottom. This only allowed a short time before the JCB’s had to leave, and shortly afterwards we were able to float… get to the dump site and get back in again before the tide turned… Tidal ranges there are some of the greatest in the world up to 40 feet I believe. But it was the quality of the stonework that amazed me… as good as the facade of any quality building in a major city centre.

It’s the construction methods where the harbour walls are to be built in deeper water where the tide never drops below the foundation level… and not just a random dumping of stone overboard, but havens where ships can berth alongside without fear of damage from underwater obstructions. The Solent forts etc… I was working the Solent while they were investigating, and then preparing to raise the Mary Rose… we passed it several times a day… due to the tides, they had very little time to work. Just a few hundred yards away is one of those forts… built in the mid 1800s without any of the modern equipment employed on the Mary Rose project?

I wonder if looking into the building of Venice may help me.

Am I right in believing it was Smeaton the designer of the Eddystone light house that promoted ‘hydraulic lime’, a cement that set under water and a forerunner to Portland Cement…

Ferval… not going off topic at all, as its mealy raised a burning question I’ve driven around the coast of Scotland trying to find an answer to… how did they in the late 1500s, dig a hole in the seabed and into a mine shaft.

I saw the BBC’s piece about the ‘Moat Pit’ on one of their ‘Coast’ episodes, but was stuck on a hospital bed at the time and wasn’t able to catch the name of it except it was a well preserved and ‘pretty’ village with pan tiled roofing brought over from the continent as ‘ballast’ from the coal ships trading there.It was the idea that they had mined out beneath the sea and then dug a shaft to facilitate extraction of water, and the coal, and add fresh air to the underground workings that caught my attention.

After discharge from hospital I did my best to find more information, and failed. The only access I had to the internet was via numerous visits to the local library where half an hour time limits were insufficient for this computer illiterate researcher to not only gain computer skills but glean the info I wanted.

As a result and still being quite ill I set off an a quest to find the damned mine by driving the entire Scottish coast, every road that lead to the sea I marked off on my map, and had a wonderful time in the process but still I failed. Not one of the hotels nor B+Bs could give any clues, nor showed any interest to this Sassenachs search for a long abandoned coal mine. Plenty of info ref Glencoe, the Clearances, and whiskey distilling though.

I went to the ‘National Mining Museum Scotland’ to visit the Lady Victoria Colliery at Newtongrange, but sadly as I parked up in the disabled parking bay I could see it was too far for me to walk to the entrance, so I missed out on that. Further down the coast I was taken ill again and spent a month in Scarborough hospital an experience that’s hard to forget and on discharge took a room in a quiet backwater country pub to rehabilitate.

What luck to discover the landlord was a former engineer at the Lady Vic mine, and quickly told me where the ‘moat pit’ was at Culross, but pronounced kooris… so as soon as I felt up to it I turned north again to see this forerunner to the industrial revolution. The annoying thing was, as I’d come over the Forth road bridge to continue my coastal route, I’d passed the mine by just ten miles as it lay up river to the bridge.

Interestingly the numerous artists’ impressions of the ‘Moat Pit’ showing a tall and slender almost submerged lighthouse structure rising from the seabed with ships moored alongside loading coal have vanished from my Google searches… after revisiting the area, I went back to the Lady Vic mine and was this time able to have a look around where I saw the same artist impressions… I wonder if they too have vanished…

Nearby there are the monumental remains of lime kilns close to a place called, with great imagination, Limekilns. The kilns are in Charlestown, it's just along to the east on the same google map. You can see the kilns behind Charlestown harbour if you zoom in. The houses in the village are alleged to be laid out to represent the initials of Charles Elgin (yes, one of the marbles Elgins) who redesigned it.

Still reading it ferval, there’s a lot to take in… but yes… went there seen all the places you mention and got the photos too. Stayed in the B+B last place in the village before you get to Longgannet… one place I didn’t get to grips with was the long arched roof structure overlooking the railway that they say is a boathouse… but it’s got no doors overlooking the water… and it’s a strange shape, must have been more difficult to construct than a more conventional building… I wondered if it may have been for ice storage or salt…

Normanhurst, In the OP you mention the Solent Forts, these, or at least one of them - the Nab Tower - was built in Shoreham Harbour, West Sussex in 1918 when my Grandparents lived on the coast road, facing the harbour and the construction site. Basically it was just a huge hollow steel and reinforced-concrete structure, built in the same way as a ship ie it was designed to float. When finished in was "launched" towed into position in the eastern approaches to the Solent, between Portsmouth and the Isle of Wight and then sunk and simply allowed to settle on the sea floor.

It was obviously a huge structure and couldn't be hidden during construction, but it's purpose (anti-submarine fort) was kept a secret and locally it was just called the "Mystery Tower". If memory serves they actually built two at Shoreham, but the war was over by the time the first (the Nab Tower) was finished and so when in position it was only used as a light-house, which it still is. The second I think was simply broken up.

Basically it was much the same approach as the emperor Claudius and his engineers used to construct the mole at his new port of Portus, just north of Ostia... that is take an old ship fill it's base with stone blocks and concrete, and sink it into place... giving a solid base to built on.EDIT : And remember concrete, even Roman concrete, will set under water, so you can built onto a permanently submerged base.

I'm sure I have some old photos taken during construction of the Nab Tower.. .. I'll try to dig them out.

Last edited by Meles meles on Mon 02 Jan 2012, 14:15; edited 3 times in total

One thing I didn't know - although I'm not surprised - is that the sea floor where the tower was put down was not quite level, and so to this day the Nab Tower leans at an angle of 3° from the vertical. However it's still very sturdy: in 1999 it was hit by a freighter which came off a lot worse in the encounter and nearly sank - the Nab Tower suffered only minor damage.

Thanks meles… yes I’ve sailed quite close to the nab many times… there’s a dumping ground just past it where we off loaded the dredged spoil from the various contract we had in and around the Solent… it’s a lonely spot, seen for miles and hardly missable, yet one banana boat must have had one too many and near demolished it in the 80s… I think.I didn’t know about the construction of the nab… but it’s not too dissimilar from the rigs then…

View overlooking Portsmouth and Langston harbour from Portsdown hill.The land in the middle left is the western tip of Hayling Island where a ferry runs to Eastney on the eastern tip of Portsmouth, centre of picture… the chimney to the right is at Fort Cumberland:

One common way of proceeding was to sink a caisson and excavate inside it, then drive piles, and pour a concrete "cob" to spread the load over numerous piles. ISTR a prog about the buildng of Brooklyn Bridge, they did something like that to get the load onto the ragstone to take the towers.

Thanks Gil… now you mention it, I recall moments of a prog where they encased themselves into a submerged wooden structure, and then had to pressurise it to prevent water entering, but at the same time experienced the first effects of ‘compression sickness’ later known as the bends… in that prog didn’t the builder, a young man taking over the construction from his father eventually die from continual ‘bends’… have I got that right… could they, would they have done the same in building the Solent forts, or any other underwater construction…? The breakwaters at Dover, Portland, Plymouth etc.

on reading the history section of the diving bell I’m astonished to see what was accomplished at depth with such antiquated gear… wasn’t the Mary Rose ‘dived’ on with a view to salvage soon after she went down.

I wish I could remember even some of the stuff I’m reading… but I can’t remember the point when it became difficult to remember, but at the same time in never ceases to amaze me how much we do know about things we never knew we knew… if you know what I mean.

Norman, as a non technical person this may all be rubbish but didn't the Romans first make a cement to use under water hence the building of bridges across the wider rivers to access Europe and the rest is history? Someone will know more.

As for quays in estuaries, wooden piles were driven in first - in many places of ancient docking these can still been seen, well pickled by now - not that pile driving is easy in any base, I imagine.

As for the use of cloth as in sandbags, it lasts far longer than plastic. A pair of jeans lost in a most tagic episode on the bay in the subcontinent where our beach hut is filled with sand still lie there, in the same place unscathed by 15 years of monsoon whipped waves pounding on them. One day I may write what happened there in another thread.

From another totally non-technical person, would some of these harbours not have been subject to changing sea and climate conditions which might have meant building was simpler than it now looks?

Earthquakes in Wellington in the 1850s meant that the land was naturally reclaimed and able to be built on, but could it not happen the opposite way where sea disappearing gives the appearance of a larger harbour than would have originally been the case?

Anyway sadly you can build on sand something that looks solid. The people in the eastern suburbs of Christchurch are learning this the hard way - their houses looked fine sitting on top of the land, but an earthquake and subsequent liquefication has meant they have wobbled all over the place with the land sinking underneath them.

But as Nordmann said earlier, people are quite ingenious in working out solutions to these technical problems and have managed to built structures that look impossible without cranes and bridges everywhere. No doubt there have been many deaths while they work out the best methods.

(On a slightly related topic, our government is apparently thinking of making work from ladders illegal - too many people falling and costing health services money. They will be allowed to use them for access but not for work. I don't suppose it will apply to diy people cleaning out the gutters. We soon won't be allowed to get up in the morning in case we have an accident and have to use hospital services.)

"(On a slightly related topic, our government is apparently thinking of making work from ladders illegal - too many people falling and costing health services money. They will be allowed to use them for access but not for work. I don't suppose it will apply to diy people cleaning out the gutters. We soon won't be allowed to get up in the morning in case we have an accident and have to use hospital services.)"

Too much emoticons make the text not easy to read, but on this I can perhaps use one...those New-Zealanders ...not that they are better overhere... if you hear some Brits about the EU regulations...

After some thought - assuming that I had been asked to build such a quay as Norm mentions, of course there is one point further to make.

You speak of the arms of a bay and a port tucked into one side. That suggests harder rock strata on that side or both. Think Lulworth cove.

Also wave strength would not be so great - weighted tree trunks heaped up to form a barrier could be used to build behind... that's trying to think like a beaver. All it needs then is some muscle and careful planning to get stones heaved into place

Norman, as a non technical person this may all be rubbish but didn't the Romans first make a cement to use under water hence the building of bridges across the wider rivers to access Europe and the rest is history? Someone will know more.

I've seen a documentary on Roman quay and bridge building techniques but, frustratingly and unhelpfully remember very little except that it was a fascinating watch!

Although any preservation of this knowledge in literary sources from the Middle Ages is unknown, medieval masons and some military engineers maintained an active tradition of using hydraulic cement in structures such as canals, fortresses, harbors, and shipbuilding facilities.[6][7] The technical knowledge of making hydraulic cement was later formalized by French and British engineers in the 18th century

It makes sense that the Greek and Romans found that using volcanic ash made a hydraulic cement that could be used in building structures in or around water, after all there is plenty of volcanic stuff lying around.

But Wiki also said that hydraulic cement was used in Medieval Britain for harbours etc, does anyone if they bought the ash in from Europe or if they used something else instead?

I’ve literally lost count the number of times I’ve past the Eddystone, a dangerous rock in the middle of otherwise deep water 8miles south of Plymouth… and each time I’ve passed it I’ve marveled at the man ‘John Smeaton’ who designed and built the first proper lighthouse there.

At the same time I’d always believed it was he that developed the idea and pioneered the use of ‘hydraulic lime’ a concrete that sets under water… and this in 1756 when construction started.

I’m somewhat surprised then to read from P’s post here that he was not the first and that it was used extensively by the Romans… but then ID makes the point it was first used by the Ancient Macedonians, obviously much further reading required here then…

Although my original point is ref the construction of old harbours and quays necessitating the laying of stone blocks etc below the water level, it does also bring to bear the question of building bridges across wide rivers, and there are plenty of examples of that.

Even by today’s standards, and I’ve been involved in a few marine civil engineering contracts… huge pontoons with heavy lift cranes, pile drivers, compressors and massive pumps and an endless supply of concrete make even the smallest job not only costly in monetary terms but also in labour and engineering skills, with what we called the ‘what if’ factor taking a huge precedence as things do go wrong. I really do marvel at the so called primitive building methods employed by our forefathers…

I don’t doubt for a moment that some of you have seen more examples than I have of roman remains, bridges, aqueducts and other marvels of past engineering, but I’m looking at a few engravings of the medieval London Bridge… and what a sight it was.

I know it was a long time ago, but I noticed Normanhurst's reference to working on St Aubin's harbour and the quality of the stonework. I happened to have visited St Aubin's a couple of weeks back (when the tide was out) and took a photo you might find interesting:

I was talking to an Irish friend the other day who in the course of the conversation mentioned "Dun Laoghaire Pier". I enquired further and discovered that there are 2 piers at Dun Loaghaire -the West Pier and the East Pier. I fondly imagined these to be Victorian cast iron and wooden structures upon which the denizens of the then Kingstown would promenade of a Sunday afternoon.

I was soon disabused of this illusion, however, as apparently the piers at Dun Laoghaire (Dunleary?) are stone breakwaters. The usage of the word 'pier' there is in the common with American English usage as in a quay or a dock.

This got me to thinking (not about stone quays as such) but about piers. Or more specifically, about Victorian pleasure piers. Something which I hadn't appreciated until then is that they are a phenomenon which are really only found in England and Wales. There is a pier on the Isle of Man but there are no piers to speak of in Scotland or Ireland. Does anyone know why this should be and are there piers elsewhere in the world such as in continental Europe, America and Australia etc?

The OED's etymology of the word "pier" supports the fact that the Irish usage to indicate a breakwater made from stone is in fact the traditional English version. It can be attested to in that sense back to the 15th century and may or may not be linked to the Old French word "pire" which meant the same thing (the doubt is only due to the fact that word apparently disappeared from traceable usage for about four hundred years between the last "pire" and the first "pier"). Its primary function as a landing stage in English remains, for cultural reasons, its definitive function in the vernacular there. Using it for pleasure purposes is incidental to this function - if no one used it as such it would still be classed as a pier.

As to why the pleasure pier was a peculiarly English invention I would assume that this is due in the main (pardon the pun) to the particular shift in demographics in the 19th century which deposited large proportions of the population to within accessible distances from the seaside, the cultural association that had already developed between the seaside and leisure, the gradual development of the concept of disposable income used in the pursuit of leisure activities and the rapid growth of this phenomenon, the pioneering improvements locally in industrial technique that facilitated piers' construction and, once all these factors came together, the rapidly attained and reinforced popular appreciation of the novelty effect of promenading some distance out into the sea. Ireland and Scotland in the first half of the 19th century only partially shared these characteristics of population spread, general disposable income, accessibility and cultural notions of leisure. However there were early imitative ventures - Edinburgh for example produced one of the earliest ever piers in 1821. Ireland, a predominantly agricultural economy with proportionately way smaller middle and industrial working classes, didn't produce any until well into the second half the century.

One place where a measurable coming together of the same factors closely correlating to England (and Wales) earlier occurred was in California in the early years of the 20th century. There, unlike Ireland whose pleasure pier construction had relatively recently preceded it but was already in decline, the pleasure pier enjoyed popular success as a leisure activity destination. A similar development occurred in Texas where Galveston still contains a popular pier modelled on the earlier English prototypes.

I wonder if the absence of pleasure piers in Scotland might have a more practical explanation. Goodness knows, we're not short of piers and standing there to fish and to watch the ferries come and go was a memorable and not infrequent pastime when I was a child but those piers were purely functional and I would suggest, importantly, fairly short. According to Wiki, the first pleasure pier was built in Ryde to accommodate passengers who, at low tide, had to be carried on a porter's back for half a mile. The pleasure piers I remember were those in the North of England: St Anne's Lytham, Southport, Morecambe. All were very long in order to reach out to open water at low tide so a stroll along the pier took quite a time and standing looking down at, and over, the sea is a major part of the experience. These great long structures then gave the space for ancillary entertainment venues to be constructed. Up here, however, the piers were shorter because of the inshore deeper water and tidal range being more vertical than horizontal and so the entertainment venues developed onshore, near to the piers rather than on them. Given the plethora of Victorian piers on the Clyde estuary and the popularity of going 'doon the watter* amongst both working class holiday makers and the middle classes sailing to their holiday villas, I don't think that the absence of pleasure piers here can be explained by just lack of popular demand but more by geological and oceanographic conditions making their construction difficult and extremely expensive.